The present invention relates generally to disassembly of layers joined by bonding, such as welding, and more particularly to disassembling at least two joined layers with vibrational energy.
As society becomes collectively more concerned with sustainable and long-term economic growth, legislative efforts emerge worldwide to demand intelligent management of natural resources. One such effort involves transferal of end-of-service life recycling responsibility to manufacturers. The implication of this policy is that original equipment manufacturers are responsible for after service recycling and final disposal of products they produce.
The adopted technical approach for product recycling varies from market to market. In North America, once the reusable components have been taken out of the product, the remaining carcass is shredded and magnetically sorted to separate ferrous metals (iron and steel) from non-magnetic metals and non-metals prior to recycling. In the European Union, however, a more stringent recycling requirement is in place mandating disassembly at the component level to recover different types of materials based on chemistry, alloy type and toxicity level. For example, current car bodies and subassemblies are fabricated from many metals which are often resistance spot-welded together. These assemblies are designed for robustness against disintegration in any service environment, contrary to the need of disassembly for recycling. To date, there is no simple process for dismantling these assemblies by disjoining the welded joints.
Therefore, there is a need in the art to provide a method for disassembling or dismantling the joined layers of an assembly or workpiece such that the layers can be easily separated for recycling. An apparatus is also needed for performing such a method such that it improves the productivity, dismantling time and reducing costs.
Accordingly, it is an object of the present invention to provide a disassembly apparatus and method for disassembling a workpiece having at least two layers joined together by welding or other bonding processes at a bonding site. The method comprises the steps of providing a fixture for holding the workpiece and placing the workpiece into the fixture. The method further includes securing the workpiece into the fixture so as to prevent movement of one of the layers and moving the sonotrode to contact the workpiece so as to apply a predetermined amount of contact pressure to the workpiece. The sonotrode in contact with the layer is then vibrated at a predetermined frequency until the layers become disassembled. In one embodiment, the vibration of the sonotrode passes into the workpiece in a direction generally perpendicular to a line through a point where the sonotrode contacts the workpiece and the bond site. The sonotrode is vibrated at a predetermined frequency, at a predetermined power range and at a predetermined amplitude. The method of the present invention will work with low frequency vibrations at a higher amplitude as well as at ultrasonic frequencies.
The present invention also provides an apparatus for disassembling multiple layers of material bonded together at bond sites. The apparatus comprises a frame, the frame including a base, a column and a head, the column connecting the base to the head, wherein the column, base and head combine to form a C-shape frame, the C-shape frame including a throat. The apparatus also includes an anvil attached to the base portion of the C-shape frame; and a disassembly tool attached to the head portion of the C-shape frame, the ultrasonic disassembly tool including a sonotrode and a sonotrode tip. A power cylinder is secured to the head, the power cylinder engaging the sonotrode and operative to drive the sonotrode into engagement with one of the layers of the workpiece. The apparatus includes a transducer operative to vibrate the sonotrode tip at a predetermined frequency, power range and amplitude to break the bond between the layers at the bond point. In one embodiment, the sonotrode is vibrated at ultrasonic frequencies.
Other objects, features and advantages of the present invention will be readily appreciated after reading the subsequent description taken in conjunction with the accompanying drawings.